Irish former athlete Sonia O'Sullivan was sceptical about Ayana's level of fatigue.

"That's a world record many people would have questioned for a long time, 23 years ago, set by the Chinese," said O'Sullivan, who won 5000m silver at the Sydney 2000 Games.

"I'm not jumping out of my seat because you question it as well yourself, how can you do that?

"How do you have an athlete that can break the world record so easily like that? She didn't look very tired afterwards."

Women's marathon record-holder Paula Radcliffe was also disbelieving, saying, "I'm not sure that I can understand that."

"When I saw the world record set in 1993, I couldn't believe what I was seeing," Radcliffe told the BBC.

"Ayana has absolutely blitzed that time."

The entire race was startlingly quick, featuring 18 personal bests and several national records.

Silver medallist Cheruiyot (29:32.53), Ethiopian bronze medallist Tirunesh Dibaba (29:42.56) and Alice Nawowuna, the Kenyan who set the early pace before finishing fourth, all ran times that Wang had only previously bettered.

It was also a triumphant morning for Australia's Eloise Wellings, who pulled off an Australian-best Olympics run.

The 33-year-old mum-of-one wiped almost 40 seconds off her personal best, finishing in 31 minutes 14.94 seconds to place 10th in the 37-strong field.

Her performance eclipsed Susan Hobson's 17th place at Atlanta 1996 and Carolyn Schuwalow's previous best Australian time of 32:10.05 at Seoul 1988.

"It made me burst into tears," Wellings said.

"It probably won't sink in until after the 5km.

"It was a pretty incredible race to be part of."

Wellings led the chase at the halfway mark and then proceeded to pick off her fading rivals one by one.

Chaos threatened amid the excitement as Ayana and her fellow frontrunners lapped most of the field, confusing some runners about how many laps they had still to complete.